Re: portgen(1) use old Makefile as template when upgrading a port

[Andrew Hewus Fresh]

This patch lets us remove the FLAVORS if we're updating a port that is
moving from supporting python 2 and 3 to only supporting one of them, it
should also better handle removing the MODPY_VERSION in the very
unlikely case that a python 3 only port adds python 2 support.

Also able to simplify things as we ended up switching to copying
everything except stuff we know we don't want.

Noticed by kmos@ when trying out py-nose that does this

Comments, OK?

Index: infrastructure/lib/OpenBSD/PortGen/Port.pm
===================================================================
RCS file: /cvs/ports/infrastructure/lib/OpenBSD/PortGen/Port.pm,v
retrieving revision 1.16
diff -u -p -r1.16 Port.pm
--- infrastructure/lib/OpenBSD/PortGen/Port.pm  14 May 2019 15:00:01 -0000      
1.16
+++ infrastructure/lib/OpenBSD/PortGen/Port.pm  14 May 2019 16:44:49 -0000
@@ -312,6 +312,9 @@ sub write_makefile
        my @template = $self->parse_makefile("Makefile.orig");
        my %copy_values;
 
+       # Decisions elsewhere might effect which values to copy from the 
template
+       my %dont_copy = %{ delete $configs{dont_copy} || {} };
+
        if (@template) {
                %copy_values = map { $_->{key} => 1 }
                    grep { $_->{name} ne 'REVISION' }
@@ -380,17 +383,10 @@ sub write_makefile
                        }
 
                        # If we didn't get a value, copy from the template
-                       # if we know we should and if so, also copy:
-                       # * MULTI_PACKAGES until we understand them
-                       # * any _DEPENDS that we didn't find
-                       # * plus any MODPY_* variables
                        if ( not $value and %copy_values ) {
-                               my $name = $line->{name};
-                               my $copy =
-                                      $copy_values{$key}
-                                   || $name =~ /_DEPENDS$/
-                                   || $name =~ /^MODPY_/;
-                               $value = $line->{value} if $copy;
+                               $value = $line->{value}
+                                   if $copy_values{$key}
+                                   and not $dont_copy{$key};
                        }
 
                        next unless defined $value;
Index: infrastructure/lib/OpenBSD/PortGen/Port/PyPI.pm
===================================================================
RCS file: /cvs/ports/infrastructure/lib/OpenBSD/PortGen/Port/PyPI.pm,v
retrieving revision 1.13
diff -u -p -r1.13 PyPI.pm
--- infrastructure/lib/OpenBSD/PortGen/Port/PyPI.pm     14 May 2019 15:00:01 
-0000      1.13
+++ infrastructure/lib/OpenBSD/PortGen/Port/PyPI.pm     14 May 2019 16:44:49 
-0000
@@ -106,10 +106,12 @@ sub fill_in_makefile
 
        if ( @versions > 1 ) {
                shift @versions; # remove default, lowest
+               $self->{dont_copy}{MODPY_VERSION} = 1;
                $self->set_other( 'FLAVORS', "python$_" ) for @versions;
                $self->set_other( 'FLAVOR',  '' );
        }
        elsif ( @versions && $versions[0] != 2 ) {
+               $self->{dont_copy}{$_} = 1 for qw( FLAVORS FLAVOR );
                $self->set_other(
                    MODPY_VERSION => "\${MODPY_DEFAULT_VERSION_$_}" )
                        for @versions;